Expression patterns of CT antigens in malignant gammopathies, exemplified by immunohistochemical staining with mAb CT7-33. (A) Homogeneous staining of MM by mAb CT7-33 with only occasional scattered immunonegative myeloma cells (arrow) (patient # 4; obj. 20x). (B) Heterogeneous CT7-33 immunoreactivity in a MM case with an overall staining of 25-50% tumor cells (patient # 6; obj. 20x). (C) Focal immunoreactivity of mAb CT7-33 with only single positive myeloma cells (patient # 12; obj. 20x). (D) Membranous CT7-33 immunoreactivity in a plasmacytoma case (patient # 26; obj. 60x).